Landing aid



LANDING AID 4 Sheets-Sheet 1 Filed May 16, 1952 INVENTORJ.

JOHN HAYS HAM Mo N 0 J R BY ALBERT D. TREN 0R 1954 J. H. HAMMOND, JR.. ETAL I 2,669,703

LANDING AID Filed May 16, 1952 4 Sheets-Sheet 2 INVENTORS JOHN HAYS HAMMOND JR. BY ALBERT D-TRENOR.

Feb. 16, 1954 LANDING AID Filed May 16, 1952 J. H. HAMMOND, JR., ET AL 4 Sheets-Sheet 3 F15. HP.

INVENTOR: JOHN HAYS HAMMOND, JR.

y ALBERT D. TRENOR--- 1954 J. H. HAMMOND, JR., ET AL ,7

LANDING AID Filed May 16, l952 4 Sheets-Sheet 4 i D I25 93 INVENTORS 64 a4 JOHN HAYS HAMMONDHJR.

F i BY ALBERT D.TRENOR.

latented Feb. 16, 1954 arena or-Fic LANDING JohnHays Hammond, J r., and Albert D. 'Titenor, Gloucester, Mass; said Trenor assignor to :said

Hammond, Jr,

Application May 16, 1952, SerialNo. 288,215

2 'Claims. 3.

This invention relates to landing .aids for air- Planes for use in fog, mist, haze, smoke or other conditions of poor visibility, particularlyat night.

The invention provides a plurality of guide paths which may be selected at will by an operator at the airport and whichdirect the pilot along the proper guide path for the particular type of plane that he is flying.

The invention also consists in certain new and riginal features of construction and combinations of parts hereinafter set forth and claimed.

The nature .of the invention as to its objects and advantages, the mode of its operation and the manner of its or anization, may be better understood by referring to the following description, taken in connection with .the accompanyin drawings forming a part thereof, in which:

Fig. 1 is a perspective view of a landing strip embodying one form of the invention,

Fig. 2 is a perspective view of a landing Strip embodying a modified form of the invention,

Fig. 3 ,is a side elevation of part of the mecha nism used to control the various light sources,

Fig. 4 is a section taken on line 4-4 of Fig. .5, and

Figs. 5, 6 and 7 are enlarged diagrammatic perspective views of part of the control mechanism shown in Fig. 3 .in various positions of operation.

Like reference characters denote like parts in the several figures of the drawing.

In the following description parts will be identified by specific names for convenience, but they are intended to he generic in their application tosimila-r parts.

Referring to the accompanying drawings and more particular-1y to Fig, 1 a landing Istrip I is provided with a first series of powerful search lights ll-l2, Iii-M, 15-15, ll-JB, etc, which, for example, may be located 50.0 feet apart and which project narrow intense beams of light crossing at 20, 21, 22, 23., etc., respectively. lllocateol ad jacent to the first series of .searchl-ights are a second series of similar search lights .2445, 26-21, 28-29, Bil-3|, etc. which pr ject beams of light crossing .at 33., 34, 35, 36, etc., respectively. Located adjacent to these sea-rchlights are a third series of searchlights 31-38, 39-40, 41-42, 43-44 etc each of which projects two horizontal beams of light in opposite directions forming a cross pattern of light 63, B4, 65, 66, etc. transverse to the landing strip '10.

All the searchlights in the .first series lI-eIB, etc. are connected by a conductor 46 and branch conductor 4.! to contact 4841f a-double pole double la throw switch .48 and all the searchlights of the second series 24-31, etc. are connected by a conductor .51 and branch conductor 52 to contact 53 .of switch '49, .All of the double beam searchlights 31-44, etc. are connected by a conductor 54 and branch conductors 5,5 and 56 to contacts 51 and 58 of switch 149. The blades of the switch 49 are connected to the movable contact of a variable resistance which is connected to one side of a battery 61 the other side of which is grounded forming a return circuit to all of the search'lights. The switch 59 may be located the control tower at the airport or other suitable location.

Operation of Fig. 1

When the control tower operator is notified that an airplane of a certain type, such for example as a D66, is approaching for a landing, he throws the switch 49 to the right, thus connecting the battery .6! to the .fi-rst series of searcmights l me thru the contact and con ductors 41 and 4.6 and to the third series of double searchlights 3145 thru the contact :58 and conductors 5t and 54. The third. series of search'lights 37- throw beams of light perpene dicular to the landing strip 1-0 producing a trans verse pattern of lighting spaced 500 feet apart, as indicated at 153-66.

The first series of :searchlights .l l-IB project narrow intense beams of light crossing at 2943, etc. :as already described, which are located at the various heights of the landing path of a D06 airplane :and are directly over the center =01 the landing strip lfi. In this system the pilot flies thru the various points ill-23 which are of decreasing altitude in such relationship to each other that the pilot of a D06 will automatically bring his airplane to the correct landing position.

If an airplane of a diiferent type such as a D03 is coming in for a landing, the control tower operator throws the switch 49 to the left thus connecting the battery -61 to the second series of searchiights :2t 3l thru the contact 53 and condoctors 52 :ands56 and to the third series of double search-lights 3. 1 thru contact 517 and conductors .5 5 and '51. This will put the thirdseries of searchlights into operation as already described.

"Ih'e second series of searchlights 24-3 project narrow intense beams of light crossing at 3345 as already described, which are located at the various heights of the landing path .59 of a DCB airplane and are (directl over the center of the landing strip to. i-In this way the ilot flies thru the variou points 3343.6 which are oil a :2 decreasing altitude in such relationship to each other that the pilot of a D03 will automatically bring his airplane to the correct landing position.

By adding any desired series of searchlights any particular landing path for any type of airplane may be produced. It is thus seen that the control tower operator by manipulating the switch 49 may select the proper landing path for the particular airplane that is making a landing.

Due to the varying density of the fogs encountered in blind landings, it has been founddesirable to vary the intensity of the Searchlight beams. This may be accomplished by the use of the variable resistor 88, which may be so adjusted as to give the proper intensity of illumination for the prevailing conditions of fog existing at the time of landing.

Instead of using a plurality of searchlights each set at a fixed angle at each station it is possible to use a single searchlight at each station which may be remotely adjustable thru a wide angular range. lfhis form of the invention is shown in Figs. 2-1 and comprises a series of remotely controlled light units 61-88, 88-18, 1I-12, 13-14, etc. The light units 61-68 and 63-18 are located outside the airport and form an approach pattern which may extend a distance 'of 3500 feet from the landing strip II).

The approach pattern may be 500 feet wide at the far end and 100 feet wide at the landing strip end and the light units may be spaced at intervals of 500 feet longitudinally.

The light units 21-12, 13-14, etc. are located along the edges of the landing strip I8.

Each of the light units 61-14, etc., two of which, 61 and 69 are shown in Fig. 3, comprises a searchlight 18 secured to a shaft 11 which is mounted for rotation in brackets 18 which are fastened to a base 19. Secured to the shaft 11 is a gear segment 88 which meshes with a pinion 8| mounted on the shaft of a synchromotor 15 also fastened to the base 19. Mounted on the base 19 and covering the entire mechanism is a transparent dome 88 of plastic or other suitable material which protects the mechanism against the elements.

For controlling the motion of the various searchlights 16 a control mechanism 82 is provided which comprises a base 83 upon which are mounted a plurality of brackets 8 1, each of which is provided with three rectangular openings 85, 86, and 81. Slidably mounted in the openings 85 and 86 are two long rectangular. shaped bars 88 and 89. Slidably mounted in the openings 81 are short racks SI, 82, etc. Secured to the bars 88 and 89 and to the racks BI, 92, etc. are a plurality of pins 63 to which are attached the ends of a plurality of springs 94 the other ends of which are attached to a;

plurality of pins 95 secured to the brackets 84. The sprin s 94 tend to hold the bars 88 and 89 and the racks 8!, 92, etc. in the positions shown in Figs. 3 and 5. Two pins 86 and 91 are secured to the bars 88 and 88 respectively and limit the motion of these bars to the left. The

bar 88 is provided with a plurality of slots 98 and 99 etc. and the bar 89 is provided with a plurality of slots I 8!, I82, etc. (see Figs. 5-7). mounted on the racks 9|, 92, etc. are a plurality of pins I03, I84, etc., which slide in the slots, 98 and IIJI, 99 and I82,etc.

Pivotally connected to the ends of the bars 88 and 89 are two links I85 and I66 the other ends of which are connected to two bell cranks III! and I38, which are rotatably mounted on two brackets H8 and III secured to the base 83. The other ends of the bell cranks I61 and 188 are connected by two links II2 and II3 to the cores Ill; and H5 of two solenoids H6 and H1, which are mounted on a bracket H8 suspended below the base 83. One side of the windings of each of the solenoids IIS and H1 are connected to one side or a battery N9 the other side of which is connected to the blade of a single pole double throw switch I2I. The two contacts I22 and I23 of this switch are connected to the other sides of the windings of the solenoids I I5 and I I1 respectively.

Meshing with the racks SI, 82, etc. are pinions I24, I25, etc. which are mounted on the shafts of synchrogenerators I26, I21, etc. mounted on the base 33. The rotor windings of all the synchrogenerators I25, I21, etc. and all the synchromotors 15 are connected together by conductors I3I and I32, which are connected to an A. 0. power source I33. The stator windings of the generator I26 are connected to the corresponding stator windings of the motor 15 of lght unit 61 by three conductors I 3-3, I35 and I33 and the stator windings of the generator I21 are connected to the corresponding stator windings of the motor 15 of light unit 69 by three conductors I31, I38, I38. The generators I26 and 521 are also connected to the motors 15 of the light units 68 and 18 by conductors not shown so that the corresponding searchlights of the light units 58 and 18 will move in unison with the searchlights of the light units 61 and 66 respectively.

The motors 15 of the light units II-12, 13-14, etc, will be controlled by a plurality of generators not shown, which are mounted on the base 83 and are controlled by the bars 88 and 88 in a manner presently to be described. The synchrogenerators and motors referred to in this description may be of any suitable type, such for example as that described in Principles of Radar, published by McGraw-Hill Book Co.,

chapter XII, section A-Synchros, pp. 12-2 to All the searchlights 16 are supplied with electric current from an external source I63 thru conductors I82 and I63 and branch conductors I18 and I19 and are controlled by a double pole single throw switch I84. One side of the line I63 is connected to two contacts i85 and I66 which engage the peripheries of two contact wheels I61 and I68. These wheels are provided with a plurality of contact segments I'I'I and I12 arranged to form a code signal, such for exexample as etc. and etc. The contact wheels I61 and I68 are mounted on but insulated from a shaft I13 which is driven at a slow speed by a motor I14 thru a reduction gearing I15. The motor I16 is supplied with current from conductors I62 and I63 thru a single throw double pole switch I16. Engag ing the peripheries of the two contact wheels of a single pole double throw switch I85. The

blade of the switch is connected by a conductor I81 to the conductor I83. A switch I88 is mserted in conductor I63 and is normally closed.

Operation of Figs. 2-9

The normal condition of the mechanism is shown in Figs. 3-5 with switch I 2I open, the solenoids H6, H1 de-energized and the bars 88 and 89 and racks 9|, 92, etc. in their right hand positions. In this condition the synchrogenerator I26, I21, etc. and synchromotors '15 are in their initial positions with the searchlights 16 pointing at an angle of 15 above the horizontal.

When the control tower operator is notified that a D06 airplane is coming .in for a landing, he closes switch I64 which turns on all the search lights 16 in the various light units 61-14, etc. He then throws the switch IZI to the right thus energizing the solenoid II1, which retracts the core II thus rotating the bell crank I08 in a counter-clockwise direction and moves the bar 89 to the left into the position shown in Fig. 6. In so doing the slot IOI in bar 89 will move to the left until its right hand end engages the pin I03 after which the pin I03 together with the slot IOI will continue to move to the left until the pin 91. engages the bracket 84. The amount of motion of the pin I03 to the left is determined by the distance from the pin I03 to the right hand end of the slot IOI when the bar 89 is in its initial position, as shown in Fig. 5.

When the pin I03 moves to the left, it causes the rack 9| to move an equal distance to the left, turning the pinion I24 thru 180 counter-clock wise, which in turn rotates the synchrogenerator I28 an equal amount from position 15 to position 45, as shown in Fig. 6. This motion is transmitted to synchromotor 15 of light unit 61 which by means of pinion BI and gear segment 80 moves Searchlight 16 from the 15 position to the 45 position as shown. This causes the beams from the searchlights 16 in light units 61 and 68 to be moved from the initial 15 positions to the 45 positions as indicated by the dotted lines MI and I42. In Fig. 2 these beams of light cross at point I43 which is a predetermined height above the ground, for example 200 feet.

When the bar 89 is moved to the left as shown in Fig. 6 the right hand end of the slot I02 will engage the pin I04 moving it to the left an amount determined by the distance from the pin I04 to the right hand end of the slot I02 when the bars 89 is in its initial position, as shown in Fig. 5. This causes the rack 92 to be moved an equal distance to the left turning the pinion I 25 thru 90 counter-clockwise, which in turn rotates the synchrogenerator I21 an equal amount from position 15 to position 30 as shown in Fig. 6. This motion is transmitted to synchromotor 15 of light unit 69 which in turn moves searchlight 16 from 15 position to the 30 position as shown. This causes the beams from the searchlights 16 in light units 69 and to be moved from the initial position to the 30' position as indicated by the dotted lines I44 and I45 in Fig. 2. These beams of light cross at point I46 which is a predetermined height above the ground for example 125 feet.

In like manner by the motion of the bar 89 the beams of light from light units 1I-12, 13-14, etc. will be rotated from their initial 15 positions to predetermined angular positions to form points of intense illumination indicated at I41, I48 etc. at predetermined heights above the ground, for example 50 feet, 25 feet, etc. The points of illumination I43, I46, I41, I48, etc. are located at the heights of the landing path I50 of a D06 airplane so that a pilot flying thru them will make a perfect landing on landing strip I0.

When a DC3 airplane is landing the switch I2! is thrown to the left thus energizing the solenoid I I6, which by means of bell crank I01 causes the bar 88 to be moved to the left, as shown in Fig. '7.

This motion of the bar 88 to the left causes the pins I03, I04, etc. together with the racks BI and 92 to be moved to the left into the positions shown, the amount of movement of each being determined by the length of the slots 98 and 99 in a manner similar to that described -in connection with Fig.6.

. The motion of the rack 91 causes the inion I24- and therefore the generator I26 to be rotated thru 270 counterclockwise from position 15? to position 60. This motion is transmitted to motors 15 causing the searchlights 16 of light units 61 and 68 to be moved from the 15 positions to the 60' positions. This causes the beams from the searchlights '16 in light units 61 and 68. to be moved from the initial 15 positions tothe 60' positions as indicated by the dotted lines 'I5I and 1.52 in Fig. 2. These beams of light cross at point I53, which is a predetermined height above the ground, for example, 250-feet.

In a like manner the motion of rack 62 causes pinion I25 and generator I21 to be rotated 180 counterclockwise from position 15 to position 45. This motion is transmitted to motors 15 causing the searchlights 16 of light units 69 and 10 to be moved from the initial 15 positions to the 45 positions as indicated by the dotted lines I54 and I55 in Fig. 2. These beams of light cross at point I56, which, for example, is at a height of 150 feet. Similarly the beams of light from light units II-12, 13-14, etc. will be rotated from their initial positions to predetermined angular positions to form points of illumination indicated at I51, I58, etc., which, for example, may be at heights of 60 feet, 30 feet, etc. The points of illumination I53, I56, I51, I58, etc. are located at the heights of the landing path I59 of a D03 airplane coming in for a landing on landing strip I0.

After each of the airplanes have landed, the switch i2I is returned to the open position thus deenergizing either solenoid H1 or II6. As soon as either of these solenoids is deenergized its corresponding mechanism including the bar 88 or 89 and rack 50 or BI is returned to its initial position as shown in Figs. 3 and 5, under the action of springs 94. This will bring searchlights 16 of all the light units back to their initial positions of 15.

When a D06 airplane is approaching for a landing, it may be desirable to identify the glide path to the pilot of the plane. In this case, the switch I64 in Fig. 3 is closed, the switch I88 is opened, the switch I is thrown to the right and the switch I16 is closed. This will cause the motor I14 to rotate the contact wheels I61 and I68 at a relatively slow rate in the direction of the arrows. As the contact wheel I68 rotates, it will make and break the circuit thru conductor I63 to all the searchlights 16 so that they will go on and off in a predetermined code sequence such as as previously described. This will identify the glide path to the pilot so that he will be sure that he is travelling along the proper glide path for a D06.

If a D03 is coming in for a landingthe switch I85 is thrown to the left and the contact wheel I61 will produce a predetermined code sequence such as In this way the pilot will be certain that he is on the proper glide path for the particular plane he is flying.

Although only a few of the various forms in which this invention may be embodied have been shown herein, it is to be understood that the invention is not limited to any specific construction but might be embodied in various forms without departing from the pirit of the invention or the scope of the appended claims.

What is claimed is:

l. A landing aid to guide an airplane along a glide path onto a landing strip comprising a plurality of light sources disposed along each side of said path, each source comprising a Searchlight projecting a beam of light across said path and adapted to swing in elevation, opposite sources projecting beams at the same elevation to cross at the center of said path, successive pairs projecting said beams at successively lower elevations to cross at points representing the selected guide paths, repeaters including receivers connected to control the elevation of said searchlights, and remote transmitters connected to actuate said receivers, and selective control means connected to actuate said transmitters to set automatically the various pairs of searchlights to 20 8 their correct respective angles to conform toa selected glide path.

2. In a landing aid, as set forth in claim 1, means connected to cause said sources to flash in a predetermined code sequence to designate the selected glide path.

JOHN HAYS HANIMOND, JR. ALBERT D. TRENOR.

References Cited in the file of this patent UNITED STATES PATENTS Number Name Date 2,081,134 Buckley May 25, 1937 2,390,109 Liebmann Dec. 4, 1945 2,597,321 Hergenrother May 20, 1952 FOREIGN PATENTS Number Country Date 402,632 Great Britain Dec. 7, 1933 

